In-pipe passive centering mechanism with radial probe or tool deployment mechanism

ABSTRACT

An in-pipe apparatus for pipe inspection or maintenance is provided. The apparatus includes: a rotational deployment mechanism to rotationally deploy a probe or tool about an inner circumference of a pipe with respect to an axis of rotation; a radial deployment mechanism to radially deploy the probe or tool in a radial direction from the axis of rotation toward a target point on the inner circumference; and a passive centering mechanism to passively align the axis of rotation with the axis of the pipe. In some embodiments, the rotational deployment mechanism includes a motor to rotate the radial deployment mechanism about the axis of rotation. In some embodiments, the apparatus further includes a longitudinal deployment mechanism to longitudinally deploy the probe or tool along the pipe axis, with the passive centering mechanism passively maintaining alignment of the axis of rotation with the pipe axis during the longitudinal deployment.

CROSS-REFERENCE TO RELATED APPLICATION

The present application claims the benefit of and priority to U.S.patent application Ser. No. 16/574,642, titled IN-PIPE PASSIVE CENTERINGMECHANISM WITH RADIAL PROBE OR TOOL DEPLOYMENT MECHANISM, filed on Sep.18, 2019, which is hereby incorporated by reference in its entirety.

FIELD OF THE DISCLOSURE

The present disclosure relates to pipeline sensing and maintenance ingeneral, and specifically to a pipeline apparatus having an in-pipepassive centering mechanism with a radial probe or tool deploymentmechanism.

BACKGROUND OF THE DISCLOSURE

In the field of automated pipeline technology, in-pipe inspections andmaintenance can be challenging tasks as they can require certainfunctions to be executed in a limited space using remotely operated orautonomous robots and crawlers. Crawlers equipped with sensory featuresand maintenance tools drive inside the pipe and perform certain tasks atspecific locations. It can be important to ensure proper deployment ofsensor probes and tool heads to achieve reliable output. In-pipe tasksoften require perpendicular deployment of probes and tools with respectto the inner walls of the pipeline in order to achieve consistent dataand results. However, this can be difficult to reliably achieve withrobotic systems given the different pipe schedules (e.g., differentinternal diameters), the various sizes of pipes, and the negotiation ofinterior obstacles such as going through weld beads.

It is in regard to these and other problems in the art that the presentdisclosure is directed to provide a technical solution for an effectivepipeline apparatus having an in-pipe passive centering mechanism with aradial probe or tool deployment mechanism.

SUMMARY OF THE DISCLOSURE

According to an embodiment, an in-pipe apparatus to inspect or maintaina pipe is provided. The apparatus includes: a rotational deploymentmechanism to rotationally deploy a probe or tool about an innercircumference of the pipe with respect to an axis of rotation; a radialdeployment mechanism to radially deploy the probe or tool in a radialdirection from the axis of rotation toward a target point on the innercircumference of the pipe; and a passive centering mechanism topassively align the axis of rotation with the axis of the pipe.

In an embodiment, the apparatus further includes a longitudinaldeployment mechanism to longitudinally deploy the probe or tool in alongitudinal direction along the axis of the pipe.

In an embodiment, a diameter of the pipe varies in the longitudinaldirection, and the passive centering mechanism passively maintainsalignment of the axis of rotation with the axis of the pipe across thevarying pipe diameter during the longitudinal deployment of the probe ortool.

In an embodiment, the rotational deployment mechanism includes a motorto rotate the radial deployment mechanism about the axis of rotation.

In an embodiment, the target point includes a plurality of target pointson the inner circumference of the pipe at a corresponding plurality ofradial directions from the axis of rotation, and the rotationaldeployment mechanism is further to rotationally deploy the probe or toolto each of the radial directions while the passive centering mechanismpassively maintains alignment of the axis of rotation with the axis ofthe pipe and the radial deployment mechanism radially deploys the probeor tool toward a corresponding one of the target points.

In an embodiment, the radial deployment mechanism includes: a firstslider to hold the probe or tool; a first linear guide to linearly guidethe first slider in the radial direction; and a linear actuator tolinearly actuate the first slider along the first linear guide, toradially deploy the probe or tool in the radial direction.

In an embodiment, the radial deployment mechanism further includes: aspring held by the first slider at a first point of attachment; a secondslider to hold the spring at a second point of attachment; and a secondlinear guide to linearly guide the second slider in the radialdirection, wherein the linear actuator is further to linearly actuatethe second slider along the second linear guide, to radially deploy theprobe or tool in the radial direction until the probe or tool touchesthe target point and the spring exerts a desired amount of force on theprobe or tool in the radial direction against the target point.

In an embodiment, the linear actuator directly linearly actuates thesecond slider along the second linear guide, and the linear actuatorindirectly linearly actuates the first slider along the first linearguide through compression or tension in the spring.

In an embodiment, the passive centering mechanism includes legs and aspring, the legs are configured to make at least three points of contactwith an inside wall of the pipe, and the spring is configured to exertoutward force on the legs and against the inside wall of the pipesufficient to passively align the axis of rotation with the axis of thepipe.

In an embodiment, the legs include wheels to longitudinally deploy theprobe or tool in a longitudinal direction along the axis of the pipe, adiameter of the pipe varies in the longitudinal direction, and theoutward force exerted by the spring is further sufficient to passivelymaintain alignment of the axis of rotation with the axis of the pipeacross the varying pipe diameter during the longitudinal deployment ofthe probe or tool.

According to another embodiment, a method of in-pipe inspection ormaintenance of a pipe is provided. The method includes: automaticallyrotationally deploying a probe or tool about an inner circumference ofthe pipe with respect to an axis of rotation; radially deploying, usinga radial deployment mechanism, the probe or tool in a radial directionfrom the axis of rotation toward a target point on the innercircumference of the pipe; and passively aligning the axis of rotationwith the axis of the pipe.

In an embodiment, the method further includes automaticallylongitudinally deploying the probe or tool in a longitudinal directionalong the axis of the pipe.

In an embodiment, a diameter of the pipe varies in the longitudinaldirection, and passively aligning the axis of rotation includespassively maintaining alignment of the axis of rotation with the axis ofthe pipe across the varying pipe diameter during the longitudinaldeployment of the probe or tool.

In an embodiment, rotationally deploying the probe or tool includesrotating the radial deployment mechanism about the axis of rotationusing a motor.

In an embodiment, the target point includes a plurality of target pointson the inner circumference of the pipe at a corresponding plurality ofradial directions from the axis of rotation, and rotationally deployingthe probe or tool further includes rotationally deploying the probe ortool to each of the radial directions while passively maintainingalignment of the axis of rotation with the axis of the pipe and theradial deployment mechanism radially deploys the probe or tool toward acorresponding one of the target points.

In an embodiment, radially deploying the probe or tool includes: holdingthe probe or tool with a first slider; and linearly actuating the firstslider in the radial direction along a first linear guide.

In an embodiment, radially deploying the probe or tool further includes:holding a spring with the first slider and with a second slider; andlinearly actuating the second slider in the radial direction along asecond linear guide until the probe or tool touches the target point andthe spring exerts a desired amount of force on the probe or tool in theradial direction against the target point.

In an embodiment, actuating the first and second sliders includes:directly linearly actuating the second slider along the second linearguide, and indirectly linearly actuating the first slider along thefirst linear guide through compression or tension in the spring.

In an embodiment, passively aligning the axis of rotation includes:making at least three points of contact with legs against an inside wallof the pipe, and exerting outward force with a spring on the legs andagainst the inside wall of the pipe sufficient to passively align theaxis of rotation with the axis of the pipe.

In an embodiment, the method further includes automaticallylongitudinally deploying the probe or tool in a longitudinal directionalong the axis of the pipe using wheels that are part of the legs,wherein a diameter of the pipe varies in the longitudinal direction, andexerting the outward force with the spring is further sufficient topassively maintain alignment of the axis of rotation with the axis ofthe pipe across the varying pipe diameter during the longitudinaldeployment of the probe or tool.

Any combinations of the various embodiments and implementationsdisclosed herein can be used. These and other aspects and features canbe appreciated from the following description of certain embodiments andthe accompanying drawings and claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an oblique cutaway view of an example pipeline apparatushaving an in-pipe passive centering mechanism with a radial deploymentmechanism for a probe or tool, according to an embodiment.

FIGS. 2A-2B are oblique cutaway views in different size pipes of anexample in-pipe passive centering mechanism, such as for use with thepipeline apparatus of FIG. 1, according to an embodiment.

FIG. 3 is a cross-sectional cutaway view of the in-pipe passivecentering mechanism of FIGS. 2A-2B.

FIG. 4 is a schematic diagram of an example pivot point adjustmentmechanism, such as for use with the in-pipe passive centering mechanismof FIGS. 2A-3, according to an embodiment.

FIG. 5 is an oblique cutaway view of an example radial deploymentmechanism, such as for use with the pipeline apparatus of FIG. 1,according to an embodiment.

FIG. 6 is a cross-sectional view of the radial deployment mechanism ofFIG. 5.

FIG. 7 is an oblique cutaway view of an example in-pipe passivecentering mechanism, such as for use with the pipeline apparatus of FIG.1, according to another embodiment.

FIG. 8 is a flow chart of an example method of in-pipe inspection ormaintenance of a pipe, according to an embodiment.

It is noted that the drawings are illustrative and not necessarily toscale.

DETAILED DESCRIPTION OF CERTAIN EMBODIMENTS OF THE DISCLOSURE

Example embodiments of the present disclosure are directed to anautomated pipeline apparatus having an in-pipe passive centeringmechanism with a radial probe or tool deployment mechanism. In one suchembodiment, simple and efficient mechanisms to center and actuate theprobe or tool inside a small diameter pipe are provided. This techniquehas less complexity than comparable automated approaches. In thistechnique, the probe or tool is deployed radially (e.g., towards thepipe inner wall) by attaching the probe or tool to a linear guidecoupled with a spring that is actuated by a linear actuator. Further,the radial deployment mechanism is supported by a rotational deploymentmechanism whose axis of rotation coincides with the axis of the pipe(e.g., line going through the center of the pipe) by a passivelyadaptable centering mechanism using another spring. Together, therotational deployment, radial deployment, and centering mechanisms makesure that the probe or tool is deployed properly (e.g., perpendicular tothe tangent line of the pipe inside wall), even for varying pipe sizes.The three mechanisms also ensure proper measurement and deploymentaround the internal circumference of the pipe. Furthermore, when thelinear actuator extends radially, the probe or tool deploys until ittouches the inside of the pipe, and the spring absorbs any additionalload experienced by the probe or tool while ensuring reliabledeployment.

As discussed earlier, in-pipe inspection and maintenance can be arigorous task as it can require certain functions to be executed in alimited space using remotely operated or autonomous robots or crawlers.Compounding these challenges includes the need for proper deployment ofthe probes and tool heads to achieve desired output. Other ways ofaddressing these concerns can rely on manual deployment of the probe ortool, or manual centering of the probe or tool (e.g., to a specific pipeschedule), or actuated centering support, where a pneumatic actuatorperforms the centering. These approaches require manual intervention(and loss of accuracy) or more operating components and complexitycompared to automated techniques disclosed herein.

Accordingly, in an example embodiment, a pipeline apparatus having arotation motor and a linear actuator to deploy probes and tools isprovided. The pipeline apparatus uses a passively adaptable centeringmechanism to center the axis of rotation of the rotation motor with theaxis of the pipe. This ensures the linear actuator radially deploys theprobe or tool consistently (e.g., perpendicularly includingsubstantially perpendicular within a few degrees of 90 degrees) to anypoint on the inside surface of the pipe, and without using any activecentering (such as with a motor, or with a guided electrical orpneumatic system, or by a manual procedure). Here, perpendicular is withrespect to a tangent line going through a target point on an inside ofthe pipe, plus or minus a few degrees, for instance, perpendicular caninclude 85 to 95 degrees. The pipeline apparatus thus combines acentering mechanism and a radial probe or tool deployment mechanism. Theradial probe or tool deployment mechanism uses a spring for reliableprobe and tool deployment. The radial probe or tool deployment mechanismalso uses a linear guide and an actuator to radially actuate the probeor tool. In addition, the pipeline apparatus aligns the axis of rotationof a rotation motor to the pipe axis to ensure reliable deployment ofthe probe or tool.

Throughout, a dry film thickness (DFT) probe is used and illustrated asan example probe or tool for use with some embodiments. Such a digitalcoating thickness gauge can use magnetic and eddy current principles tomeasure the coating thickness on ferrous and non-ferrous metals using aprobe. However, this probe should be deployed perpendicularly on thesurface of interest to take a reliable measurement, within the range of“perpendicular” noted previously. While the DFT probe is used throughoutfor convenience of description, other embodiments are not so limited.For example, in some embodiments, other probes (such as an ultrasonicthickness probe) or tools serve as example probes or tools for in-pipepassive centering and radial deployment. Such pipeline apparatuses areable to take reliable readings (or reliably deploy tools) in differentpipe schedules, with the probe or tool being rotationally deployed inconjunction with a centering mechanism such that the probe or tool canbe rotated evenly distanced from the pipe wall. Changing pipe schedulesor sizes causes a passive re-centering of the apparatus such that theprobe or tool still rotates at an even distance (spacing) from the pipewall. As such, the centering mechanism ensures that the probe or toolholder is centered and deploys properly in all applicable sizes of pipe.

In an embodiment, an automated pipeline apparatus employs severalmechanical systems, including a rotation mechanism for rotationaldeployment of a probe or tool within a pipe, a centering mechanism tocenter the rotation mechanism passively inside the pipe (e.g., withrespect to the pipe axis, such as aligning the axis of rotation of therotation mechanism with the pipe axis), a radial deployment mechanismfor radially deploying the probe or tool onto the pipe wall to take themeasurement or perform the tool operation, and a longitudinal deploymentmechanism (e.g., wheels and a motor) to move the probe or toollongitudinally along the inside of the pipe. The centering mechanismfurther maintains the centering (e.g., alignment of the axis of rotationof the rotation mechanism with the pipe axis) during the longitudinaldeployment, even when the inside pipe diameter changes or varies in thelongitudinal direction.

FIG. 1 is an oblique cutaway view of an example pipeline apparatus 100having an in-pipe passive centering mechanism 110 with a radial probe ortool deployment mechanism 120, according to an embodiment. The pipelineapparatus 100 further includes a rotational deployment mechanism 130(e.g., a servo motor) and a longitudinal deployment mechanism 140 (e.g.,including another passive centering mechanism, or part of the existingpassive centering mechanism).

In further detail, the passive centering mechanism 110 is illustrated asa tri-wheel (three sets of wheels) configuration, each wheel set offset120° from the other wheel sets in the rotational dimension of the insidepipe. Equal outward force against the inside wall of the pipe is exertedby each of the wheel sets, to center the apparatus 100 regardless ofpipe diameter. The wheel sets also permit movement of the apparatus inthe longitudinal dimension. Since the centering mechanism 110 ispassive, there are no motors or guided (or manual) steps involved in thecentering. Instead, simple mechanical forces are used for the centering,such as springs, as illustrated in the embodiments illustrated anddiscussed below in connection with FIGS. 2A, 2B, 3, 4 and the furtherembodiment in FIG. 7.

The radial deployment mechanism 120 deploys a probe or tool in theradial dimension inside the pipe. As such, the radial deploymentmechanism 120 includes, in one embodiment, a linear actuator to deploythe probe or tool in a radial direction (e.g., from the axis of the pipeto a target point on a deployment circumference 150 of the inner pipe).The radial deployment of the probe or tool is perpendicular to thetarget point on the deployment circumference 150 (such as perpendicularto a tangent line of the deployment circumference 150 at the targetpoint). Further details are described in connection with FIGS. 5 and 6below.

The rotational deployment mechanism 130 rotationally deploys the probeor tool about an axis of rotation that is aligned to the pipe axis bythe passive centering mechanism 110. For example, the rotationaldeployment mechanism 130 can be a servo motor coupled to the radialdeployment mechanism 120 and that rotates the radial deploymentmechanism 120 about the pipe axis to reach the desired amount ofrotation (while tracing the deployment circumference 150 of the probe ortool in the process).

The longitudinal deployment mechanism 140 (such as a motor and wheels)moves the apparatus 100, including the probe or tool, longitudinallyalong the inside of the pipe (in the direction of the pipe axis, or inthe longitudinal dimension). The longitudinal deployment mechanism 140can adjust the deployment circumference 150 of the probe or tool throughthis longitudinal deployment or movement. For example, in an embodiment,the longitudinal deployment mechanism includes a motor to rotate one ormore axles that drive a corresponding one or more sets of wheels (alongwith the rest of the apparatus 100) in the longitudinal direction. As anexample, the longitudinal movement of the apparatus 100 can be for a setor predetermined distance, or to a set or predetermined location, or thelike. Together, the longitudinal deployment mechanism 140 in combinationwith the radial deployment mechanism 120 and rotational deploymentmechanism 130 (as centered or aligned by the passive centering mechanism110) can allow the probe or tool to deploy consistently (e.g.,perpendicularly) and reliably to any point on the inside of the pipe.

FIGS. 2A-2B are oblique cutaway views in different size pipes of anexample in-pipe passive centering mechanism, such as the passivecentering mechanism 110 for use with the pipeline apparatus 100 of FIG.1, according to an embodiment. The passive centering mechanism includeswheels 210 arranged in three sets of two wheels apiece (six wheelstotal), each wheel set being offset 120° from each other about the pipeaxis. The wheels 210 are connected by supports or legs (one wheel perleg, six legs total) to two sliding rings 220 (three wheels per slidingring, one from each wheel set) along an axle aligned with the axis ofthe pipe.

The two legs (or supports) of each wheel set are further connected toeach other at a pivot point 230 to allow the wheel set to expand orcontract in order to adjust to the inside pipe diameter. FIG. 2Aillustrates the wheel sets expanded for a large diameter pipe while FIG.2B illustrates the wheel sets contracted for a small diameter pipe. Acompression spring 240 exerts inward longitudinal force on the slidingring 220 to expand the wheel sets to fit the inside diameter of thepipe. Put another way, the sliding rings 220, legs, and pivot points 230convert the inward longitudinal force of the compression spring 240 toan outward force on each of the wheels 210 against the inside wall ofthe pipe. This passively centers or aligns the axle of the centeringmechanism with the pipe axis, regardless of the pipe diameter orschedule. Strictly speaking, the passive centering mechanism isconstrained to a certain minimum size and a certain maximum size, butthat range is adjustable depending on factors such as length of thelegs, location of the pivot points 230, strength of the compressionspring 240, and the like. As such, for ease of description, the range istreated as unbounded.

Before inserting the centering mechanism inside a pipe, the compressionspring 240 keeps the two wheels 210 of each wheel set at the maximumextended position, which needs to be larger than the maximum inner pipediameter for which passive centering is to be accomplished. Once thecentering mechanism is inserted inside the pipe, all the supportinglinks (or legs) push together the sliding rings 220. This ensures thecentricity of the shaft and module. Hence, the sliding rings 220compress the spring 240 and this compression provides the required forceto keep the wheels 210 attached to the pipe walls and to keep the modulecentered. It should be noted that in some embodiments, the spring 240itself can be tuned to control the force delivered, such as using astronger or weaker spring to get a more desired force.

FIG. 3 is a cross-sectional cutaway view of the in-pipe passivecentering mechanism of FIGS. 2A-2B. Because of the orientation, thewheel sets in FIG. 3 each appear as single wheels 210, and only onesliding ring 220 is visible as well. The passive centering mechanism ofFIGS. 2A-3 is built on a tri-wheel configuration, as visible in FIG. 3.By building a symmetric pattern of wheel sets about the pipe axis, theoutward force attributed to the compression spring 240 is opposed bycomparable opposite forces exerted by the inside wall of the pipe, whichcenters the mechanism with respect to the pipe axis. In otherembodiments, the design is adapted for additional numbers of wheel sets(e.g., to have more rigid support) or different symmetries about thepipe axis. The design is primarily based on a four-bar linkagemechanism, where all the wheel supports (or legs) have the same lengthand are coupled with one compression spring 240 which pushes themsimultaneously to attach to the inner wall of the pipe and therebyachieve centering. This mechanism is designed to go through (pass over)weld beads and different pipeline schedules without manual adjustment oractuation, all while still maintaining centering or alignment with thepipe axis.

FIG. 4 is a schematic diagram of an example pivot point adjustmentmechanism 400, such as for use with the in-pipe passive centeringmechanism of FIGS. 2A-3, according to an embodiment. For ease ofdescription, FIG. 4 is described and illustrated in terms of the passivecentering mechanism of FIGS. 2A-3, including wheels 210, sliding ringattachments 220, and pivot points 230. The legs (support links) in thepivot point adjustment mechanism 400 each have four slots for possiblepivot point locations. In other embodiments, different numbers of slots(or variably-sized pivot point attachments) are provided. If, forexample, a stronger or weaker grip (or force on the inside wall of thepipe) is desired, the pivot point 230 can be adjusted to acquiredifferent grip strengths (force levels). For example, moving the pivotpoint 230 closer to the wheels 210 produces a stronger grip (largerforce on the inside wall), while moving the pivot point 230 closer tothe sliding ring attachments 220 produces a weaker grip (smaller forceon the inside wall). Likewise, when the centering mechanism is insertedinside a different pipe size, an equivalent grip force can be maintainedby adjusting the pivot points 230 of the support links (e.g., closer tothe wheels 210 when moving to a larger pipe size, and closer to thesliding rings 220 when moving to a smaller pipe size).

FIG. 5 is an oblique cutaway view of example rotational and radialdeployment mechanisms 500, such as for use in deploying a probe or toolusing the pipeline apparatus 100 of FIG. 1, according to an embodiment.FIG. 6 is a cross-sectional view of the rotational and radial deploymentmechanisms 500 of FIG. 5. The illustrated deployment mechanism includesservo motor 510 for rotating a radial deployment mechanism 520 about anaxis of rotation (e.g., aligned with the pipe axis by a passivecentering mechanism as described elsewhere). The radial deployment caninclude, for example, rotating the radial deployment mechanism 520 toenable radial deployment of the probe or tool to a specific target point(e.g., specific angle of rotation) on the inside of the pipe.

Referring to FIGS. 5 and 6, the radial deployment mechanism 520 includesa probe 530 (such as a DFT probe) coupled or attached to a probe slider540. For example, the probe slider 540 can be firmly attached to theprobe 530 such that the two structures move as a unit. The probe slider540 is configured to move radially along a (probe) linear guide 550. Theprobe slider 540 is also coupled to, attached to, or in contact with (orconfigured to contact) a spring 560, such as at one end of the spring560. The spring can be a compression spring or a tension spring,depending on the embodiment. The other end of the spring 560 is coupledto, attached to, or in contact with (or configured to contact) a springslider 570. For example, the spring slider 570 can be firmly attached tothe other end of the spring 560 such that the spring slider 570 and theother end of the spring 560 move as a unit.

The spring slider 570 is configured to move radially along a (spring)linear guide 580 under the control of a linear actuator 590 which iscoupled to the spring slider 570 and drives the spring slider 570 alongthe spring linear guide 580. As such, the coupling, attachment, orcontact of the spring 560 and the probe slider 540 causes the probeslider 540 and the probe 530 to move concurrently, if notsimultaneously, in the radial direction when the linear actuatoractuates the spring slider 570 and its spring 560. Accordingly, theradial deployment mechanism 520 linearly actuates the spring slider 570along the spring linear guide 580, to radially deploy the probe 530 inthe radial direction until the probe 530 touches the target point on theinside wall of the pipe and the spring 560 exerts a desired amount ofoutward force on the probe 530 in the radial direction against thetarget point.

Briefly, the probe 530 is deployed and retracted to take measurementsusing the linear actuator 590 and the motor 510 that rotates the probeholder 540. The mechanism 520 includes the spring slider 570 that isactuated by the linear actuator 590 to push the spring 560. The spring560 transfers the motion to the probe holder 540 which is linearlyconstrained using another slider 540 and linear guide 550 pair. Thespring 560 also aids the deployment of the probe 530 and ensures thatthe probe 530 is pressed with the required force on the pipe wall totake reliable measurements. Thus, the combination of a passive adaptablecentering mechanism and a consistent probe or tool deployment mechanismoffers reliable results to deploy a probe or tool and account for thedifferent pipes sizes.

FIG. 7 is an oblique cutaway view of an example in-pipe passivecentering mechanism 700, such as for use with the pipeline apparatus 100of FIG. 1, according to another embodiment. The centering mechanism 700of FIG. 7 differs from that of FIGS. 2A-3 in several aspects. For one,the compression spring 240 is replaced with a tension spring 745 placedbetween the sliding rings (e.g., within the supporting links or legs, toinwardly contract the sliding rings). For another, the wheels 715 in thewheel sets of the centering mechanism 700 are arranged laterally (e.g.,side-to-side), as opposed to longitudinally in the centering mechanismof FIGS. 2A-3. For yet another, the legs (or support links) in centeringmechanism 700 are joined at the ends to a common axle for the two wheels715 in each wheel set (and thus, there are no pivot points like thepivot points 230 in the centering mechanism of FIGS. 2A-3). Differentembodiments are possible by combining different subsets of the previousembodiments, in order to establish a passive centering structureconsistent with the present disclosure. As such, features such as thenumber, type, and location of springs in the pipeline apparatus can varybetween embodiments.

For example, in the embodiment of FIG. 7, the centering mechanism 700 ispivoted at both ends of each of the support links such that one endpivots at the sliding ring and the other end pivots at the wheels 715.Before inserting the mechanism 700 inside the pipe, the wheels 715 arepushed to spread the legs (support links) to their maximum lengthposition as the spring 745 applies tension to return to its originalposition. Once the mechanism 700 is inserted inside the pipe, the wheels715 push the sliding rings, which stretches the spring 745. Thestretched spring 745 provides the required force to keep the wheels 715attached to the pipe walls and the module centered. Since the supportingmembers are all the same length for the three wheels (wheel sets),centering is achieved. In another embodiment, to achieve the centeringusing a similar mechanism to mechanism 700, the tension spring 745 isreplaced with a compression spring placed outside one of the slidingrings.

FIG. 8 is a flow chart of an example method 800 for in-pipe inspectionor maintenance of a pipe, such as for use by the pipeline apparatus 100,according to an embodiment. Some or all of the method 800 can beperformed using components and techniques illustrated in FIGS. 1-7.Portions of this and other methods disclosed herein can be performed onor using a custom or preprogrammed logic device, circuit, or processor,such as a programmable logic circuit (PLC), computer, software, or othercircuit (e.g., ASIC, FPGA) configured by code or logic to carry outtheir assigned task. The device, circuit, or processor can be, forexample, a dedicated or shared hardware device (such as a laptop, aworkstation, a tablet, a smartphone, part of a server, or a dedicatedhardware circuit, as in an FPGA or ASIC, or the like), or computerserver, or a portion of a server or computer system. The device,circuit, or processor can include a non-transitory computer readablemedium (CRM, such as read-only memory (ROM), flash drive, or disk drive)storing instructions that, when executed on one or more processors,cause portions of the method 800 (or other disclosed method) to becarried out. It should be noted that in other embodiments, the order ofthe operations can be varied, and that some of the operations can beomitted.

In the example method 800, processing begins with automaticallyrotationally deploying 810 a probe or tool about an inner circumferenceof the pipe with respect to an axis of rotation. This can be done, forexample, using the servo motor 510 under control of correspondingelectronics configured by code or logic to drive the servo motor 510 torotate the tool or probe to the appropriate angle of rotation to deployto a desired target point on the inner wall of the pipe. The method 800further includes radially deploying 820 the probe or tool in a radialdirection from the axis of rotation toward the target point on the innercircumference of the pipe. This can be done, for example, using theradial deployment mechanism 520. The method 800 also includes passivelyaligning 830 the axis of rotation with the axis of the pipe. This can bedone, for example, using the passive centering mechanism 110.

In addition, the method 800 includes automatically longitudinallydeploying 840 the probe or tool in a longitudinal direction along theaxis of the pipe. The can be done, for example, using wheels 210, amotor, and control circuitry configured by code or other logic to drivethe apparatus in the longitudinal direction to the appropriatelongitudinal position to deploy the probe or tool. Further, the method800 includes passively maintaining 850 alignment of the axis of rotationwith the axis of the pipe across varying pipe diameters during thelongitudinal deployment of the probe or tool. This can be accomplished,for example, using the passive centering mechanism 110.

The methods described herein may be performed in part or in full bysoftware or firmware in machine readable form on a tangible (e.g.,non-transitory) storage medium. For example, the software or firmwaremay be in the form of a computer program including computer program codeadapted to perform some or all of the steps of any of the methodsdescribed herein when the program is run on a computer or suitablehardware device (e.g., FPGA), and where the computer program may beembodied on a computer readable medium. Examples of tangible storagemedia include computer storage devices having computer-readable mediasuch as disks, thumb drives, flash memory, and the like, and do notinclude propagated signals. Propagated signals may be present in atangible storage media, but propagated signals by themselves are notexamples of tangible storage media. The software can be suitable forexecution on a parallel processor or a serial processor such that themethod steps may be carried out in any suitable order, orsimultaneously.

It is to be further understood that like or similar numerals in thedrawings represent like or similar elements through the several figures,and that not all components or steps described and illustrated withreference to the figures are required for all embodiments orarrangements.

The terminology used herein is for the purpose of describing particularembodiments only and is not intended to be limiting of the scope of thepresent disclosure. As used herein, the singular forms “a,” “an,” and“the” are intended to include the plural forms as well, unless thecontext clearly indicates otherwise. It will be further understood thatthe terms “comprises” and/or “comprising,” when used in thisspecification, specify the presence of stated features, integers, steps,operations, elements, and/or components, but do not preclude thepresence or addition of one or more other features, integers, steps,operations, elements, components, and/or groups thereof.

Terms of orientation are used herein merely for purposes of conventionand referencing, and are not to be construed as limiting. However, it isrecognized these terms could be used with reference to a viewer.Accordingly, no limitations are implied or to be inferred. In addition,the use of ordinal numbers (e.g., first, second, third) is fordistinction and not counting. For example, the use of “third” does notimply there is a corresponding “first” or “second.” Also, thephraseology and terminology used herein is for the purpose ofdescription and should not be regarded as limiting. The use of“including,” “comprising,” “having,” “containing,” “involving,” andvariations thereof herein, is meant to encompass the items listedthereafter and equivalents thereof as well as additional items.

While the disclosure has described several exemplary embodiments, itwill be understood by those skilled in the art that various changes maybe made, and equivalents may be substituted for elements thereof,without departing from the spirit and scope of the invention. Inaddition, many modifications will be appreciated by those skilled in theart to adapt a particular instrument, situation, or material toembodiments of the disclosure without departing from the essential scopethereof. Therefore, it is intended that the invention not be limited tothe particular embodiments disclosed, or to the best mode contemplatedfor carrying out this invention, but that the invention will include allembodiments falling within the scope of the appended claims.

1. An in-pipe apparatus for pipe inspection or maintenance, theapparatus comprising: a rotational deployment mechanism configured torotationally deploy a probe or tool about an inner circumference of apipe with respect to an axis of rotation; a radial deployment mechanismconfigured to radially deploy the probe or tool in a radial directionfrom the axis of rotation toward a target point on the innercircumference of the pipe; and a passive centering mechanism topassively align the axis of rotation with the axis of the pipe, whereinthe passive centering mechanism comprises legs and a spring, the legsare configured to make at least three points of contact with an insidewall of the pipe, and the spring is configured to exert outward force onthe legs and against the inside wall of the pipe sufficient to passivelyalign the axis of rotation with the axis of the pipe.
 2. The apparatusof claim 1, further comprising a longitudinal deployment mechanismconfigured to longitudinally deploy the probe or tool in a longitudinaldirection along the axis of the pipe.
 3. The apparatus of claim 2,wherein a diameter of the pipe varies in the longitudinal direction, andthe passive centering mechanism passively maintains alignment of theaxis of rotation with the axis of the pipe across the varying pipediameter during the longitudinal deployment of the probe or tool.
 4. Theapparatus of claim 1, wherein the rotational deployment mechanismcomprises a motor to rotate the radial deployment mechanism about theaxis of rotation.
 5. The apparatus of claim 4, wherein the target pointcomprises a plurality of target points on the inner circumference of thepipe at a corresponding plurality of radial directions from the axis ofrotation, and the rotational deployment mechanism is further configuredto rotationally deploy the probe or tool to each of the radialdirections while the passive centering mechanism passively maintainsalignment of the axis of rotation with the axis of the pipe and theradial deployment mechanism radially deploys the probe or tool toward acorresponding one of the target points.
 6. The apparatus of claim 1,wherein the radial deployment mechanism comprises: a first slider tohold the probe or tool; a first linear guide to linearly guide the firstslider in the radial direction; and a linear actuator to linearlyactuate the first slider along the first linear guide, to radiallydeploy the probe or tool in the radial direction.
 7. The apparatus ofclaim 6, wherein the radial deployment mechanism further comprises: aspring held by the first slider at a first point of attachment; a secondslider to hold the spring at a second point of attachment; and a secondlinear guide to linearly guide the second slider in the radialdirection, wherein the linear actuator is further to linearly actuatethe second slider along the second linear guide, to radially deploy theprobe or tool in the radial direction until the probe or tool touchesthe target point and the spring exerts a desired amount of force on theprobe or tool in the radial direction against the target point.
 8. Theapparatus of claim 7, wherein the linear actuator directly linearlyactuates the second slider along the second linear guide, and the linearactuator indirectly linearly actuates the first slider along the firstlinear guide through compression or tension in the spring.
 9. (canceled)10. The apparatus of claim 1, wherein the legs comprise wheels tolongitudinally deploy the probe or tool in a longitudinal directionalong the axis of the pipe, a diameter of the pipe varies in thelongitudinal direction, and the outward force exerted by the spring isfurther sufficient to passively maintain alignment of the axis ofrotation with the axis of the pipe across the varying pipe diameterduring the longitudinal deployment of the probe or tool.
 11. A method ofin-pipe inspection or maintenance of a pipe, the method comprising:automatically rotationally deploying a probe or tool about an innercircumference of the pipe with respect to an axis of rotation; radiallydeploying, using a radial deployment mechanism, the probe or tool in aradial direction from the axis of rotation toward a target point on theinner circumference of the pipe; and passively aligning the axis ofrotation with the axis of the pipe, wherein passively aligning the axisof rotation comprises: making at least three points of contact with legsagainst an inside wall of the pipe; and exerting outward force with aspring on the legs and against the inside wall of the pipe sufficient topassively align the axis of rotation with the axis of the pipe.
 12. Themethod of claim 11, further comprising automatically longitudinallydeploying the probe or tool in a longitudinal direction along the axisof the pipe.
 13. The method of claim 12, wherein a diameter of the pipevaries in the longitudinal direction, and passively aligning the axis ofrotation comprises passively maintaining alignment of the axis ofrotation with the axis of the pipe across the varying pipe diameterduring the longitudinal deployment of the probe or tool.
 14. The methodof claim 11, wherein rotationally deploying the probe or tool comprisesrotating the radial deployment mechanism about the axis of rotationusing a motor.
 15. The method of claim 14, wherein the target pointcomprises a plurality of target points on the inner circumference of thepipe at a corresponding plurality of radial directions from the axis ofrotation, and rotationally deploying the probe or tool further comprisesrotationally deploying the probe or tool to each of the radialdirections while passively maintaining alignment of the axis of rotationwith the axis of the pipe and the radial deployment mechanism radiallydeploys the probe or tool toward a corresponding one of the targetpoints.
 16. The method of claim 11, wherein radially deploying the probeor tool comprises: holding the probe or tool with a first slider; andlinearly actuating the first slider in the radial direction along afirst linear guide.
 17. The method of claim 16, wherein radiallydeploying the probe or tool further comprises: holding a spring with thefirst slider and with a second slider; and linearly actuating the secondslider in the radial direction along a second linear guide until theprobe or tool touches the target point and the spring exerts a desiredamount of force on the probe or tool in the radial direction against thetarget point.
 18. The method of claim 17, wherein actuating the firstand second sliders comprises: directly linearly actuating the secondslider along the second linear guide, and indirectly linearly actuatingthe first slider along the first linear guide through compression ortension in the spring.
 19. (canceled)
 20. The method of claim 11,further comprising automatically longitudinally deploying the probe ortool in a longitudinal direction along the axis of the pipe using wheelsthat are part of the legs, wherein a diameter of the pipe varies in thelongitudinal direction, and exerting the outward force with the springis further sufficient to passively maintain alignment of the axis ofrotation with the axis of the pipe across the varying pipe diameterduring the longitudinal deployment of the probe or tool.